1. Field of the Invention
This invention relates in general to vehicles of the type which have implements detachably mounted thereon, and is concerned in particular with an improved coupling arrangement for such implements, wherein a take-up frame is adjustably carried on the vehicle, with coupling elements on the take-up frame arranged to coact in detachable engagement with counter-coupling elements on the implement.
2. Description of the Prior Art
An example of a vehicle of the abovementioned type is shown in U.S. Pat. No. 3,822,751 issued July 9, 1974. Here, the implement is a blade, and the coupling elements of the take-up frame and the blade comprise mutually alignable eyes adapted to receive linchpins. The problem with this type of arrangement, however, is that should a coupling operation be required to take place on uneven terrain, then it becomes difficult to achieve the necessary alignment of the eyes prior to insertion of the linchpins. This often results in considerable lost time. Moveover, personnel in addition to the vehicle operator are required to assist in the aforesaid alignment of the eyes as well as in the manual insertion or removal of the linchpins.
3. Summary of the Present Invention
The present invention has as its basic objective the provision of an improved coupling arrangement which enables both coupling and disengagement to take place without having to precisely align the take-up frame with the implement, thereby making it possible to efficiently effect coupling and detachment under all conditions, even where the terrain is uneven and the alignment between the vehicle and the implement is not exact.
A further objective of the present invention is the provision of a coupling arrangement which enables the vehicle operator to effect coupling and disengagement without assistance from additional personnel.
In the preferred embodiment of the invention to be described hereinafter in greater detail, these objectives are achieved by providing the vehicle with a take-up frame and the implement with a mounting plate arranged in a substantially vertical plane extending transversely with respect to the working direction of the implement and the vehicle. The upper portion of the mounting plate carries a counter-coupling element in the form of a rearwardly projecting open hook arranged to coact in mechanical engagement with a coupling element in the form of a horizontal pin extending between two cheek plates on the take-up frame. Adjusting devices are provided for vertically and angularly adjusting the take-up frame. During a coupling operation, the vehicle is moved towards the implement until the horizontal pin of the take-up frame contacts the mounting plate on the implement. Thereafter, the aforesaid adjusting devices are employed to elevate the take-up frame to mechanically engage the horizontal pin with the rearwardly projecting hook and to raise the implement slightly above ground level. The adjusting devices are then further employed to rearwardly incline the take-up frame, thereby causing the implement to swing against the take-up frame, thus completing the coupling operation.
The mechanical engagement of the horizontal pin with the rearwardly protruding hook can be accomplished remotely by the vehicle operator while he remains seated in the vehicle cab, without assistance from other personnel, and even under conditions where the terrain is uneven and the vehicle and implement are not precisely aligned one with the other. The two cheek plates on the mounting frame receive the rearwardly protruding hook therebetween and thereby insure appropriate centering of the implement with respect to the take-up frame and the vehicle.
Preferably, the aforesaid hook opens downwardly and the horizontal pin is elevated during the coupling operation. This enables the upper portion of the mounting plate and the hook protruding rearwardly therefrom to remain visible to the vehicle operator during the initial stages of the coupling operation, thus serving as reference points to assist in guidance.
Preferably, the rearwardly protruding hook is in the form of a triangle, the base of which is connected to the mounting plate and the apex of which points downwardly. This arrangement facilitates insertion of the hook between the cheek plates of the mounting frame.
Preferably, the length of the base of the aforesaid triangle is just slightly less than the spacing between the cheek plates. With this arrangement, once the hook is inserted over the horizontal pin and is located between the cheek plates, lateral movement of the implement in relation to the take-up frame will be prevented by virtue of the fact that the base of the hook will be laterally confined between the cheek plates.
Advantageously, the mounting plate is in the form of an isosceles triangle, the upper portion of which supports the rearwardly protruding hook. The triangular shape of the mounting plate assists the vehicle operator during initial alignment of the vehicle with the implement, and thereby further facilitates the coupling operation.
Preferably, the rearwardly protruding hook has an L-shaped cross section with one leg protruding horizontally from the upper portion of the mounting plate, and with the other leg extending downwardly and being inclined slightly away from the mounting plate.
An important advantage of the present invention lies in the fact that coupling can be effected even though the implement has an uneven load distribution. In practice, it seldom happens that the implement is evenly balanced. This can be due in part to the fact that the implements have asymmetrically arranged drives, or for other reasons such as for example unequal loading of dirt, snow, etc. during actual working. Such uneven load distributions do not adversely affect the coupling operation of the present invention, however, since there is a self-leveling effect which takes place once the hook has been engaged over the horizontal pin and the take-up frame has been raised to elevate the implement above ground level.